Studies On The Biological Characteristics And Promoting Effect Of Endogenous Bacillus From Poa Pratensis In Xining

Poa pratensis is a sort of eximious pasture which has high nutrition and yield, better adaptability.Basillus has comprehensive utilize value,especially in promoting effects of plants.Use Endogenous Bacillus which screened from Poa pratensis can advance virescence and also has good effects on farming economy.This research screened 3 strains from Poa pratensis roots,which collected from Xining botanical garden and Huzhu county.They are named zsh-1,zsh-2 and zsh-3.By studying the biological characteristics of the three strains,it was shown that they are all Gram-positive(G +) Bacillus.Endospore is located in the middle or end, sporangium is not expansion.The colonial morphology of zsh-1 is white,rough surface,irregular edge,was jagged or wavy,with the culture time prolonged,can become a colony of white milk and has fold-like uplift,with circumjacent flagella.The colonial morphology of zsh-2 is white,the surface rough,hair-like edges and has lateral flagella.The early colony of zsh-3 is pink,with the culture time extended,and the colony may have folds into brown-like uplift,has circumjacent flagella.Combination of colony morphology and physiological and biochemical test results,zsh-1 and the zsh-3 may be initially identified as Bacillus subtilis,zsh-2 may be initially identified as Bacillus licheniformis.Endophytic colonization studies have shown that the colonial amount of pouring soil inoculation is the largest,the second is daubing inoculation and the third is dipping seeds inoculation.the colonial amount of zsh-1 is the largest in three strains. Soaking in different concentrations of bacillus colonization measurement results show that the colonial amount is reduce with concentrations of bacillus colonization.The results of soaking in different time show that the colonial amount is increase when prolong soaking time.This shows that the concentration of different soaking and soaking time for different strains to enter the plant must have affected.The study of promoting effect shows that the promoting effect of zsh-1 is the most obviously and pouring soil is the best of three methods.Pouring soil byzsh-1 can enhance root length and whole length by 103.79%and 47.01%compared to the control,enhance fresh weight and dry weight by 67.59%and 141.48%compared with control.Strains zsh-1 and zsh-3 can enhance chlorophyll content of plant by 20.48% and 11.88%,strain zsh-2 has no effect in chlorophyll content.Optimized experiments of fermentation conditions show that the optimum medium of zsh-1 and zsh-3 is cucrose 10g,ammonium sulfate 5g,sodium chloride 3g, potassium dihydrogen phosphate 1.5g,the optimum medium of zsh-2 is cucrose 15g, ammonium sulfate 5g,sodium chloride 1g,potassium dihydrogen phosphate 4.5g. The optimum fermentation conditions of strain zsh-1 is inoculation quantity as 3%, culture temperature as 30℃,initial pH value as 6.5,culture time as 36h;strain zsh-2 is inoculation quantity as 5%,culture temperature as 28℃,initial pH value as 6.5, culture time as 40h;strain zsh-3 is inoculation quantity as 5%,culture temperature as 28℃,initial pH value as 6.5,culture time as 40h.